Abstract

The acoustic flyover signature of modern aircraft in their approach configuration - i.e. with slats, flaps and gears deployed - are often dominated by airframe noise contributions. To study relevant source and radiation characteristics, airframe noise tests were performed in the German-Dutch Wind Tunnel employing- for the first time ever - full-scale landing gears of an A320 aircraft. Farfield noise characteristics were determined for different gear configurations (starting form the base configuration and subsequently covering ever more gear elements with streamlined fairings) at wind speeds ranging from 40 to 78m/s. Aerodynamically generated noise from landing gears turnes out to be of broadband nature with constant levels (in 1/3-oct. bands) up to several kHz. One most essential result therefore is that landing gear noise, is not at all a &quot;low-frequency phenomenon&quot;. Moreover, levels increase with the 6th power of flow velocity.